PCT Application WO 01/01025 (“the '025 application), published Jan. 4, 2001, describes in detail manufacture and operation of pump and valve systems microfabricated from elastomer materials. The '025 application is hereby incorporated by reference in its entirety.
FIG. 7B shows a cross-sectional view of one embodiment of a non-actuated valve structure described in the '025 application. The valve structure comprises control recess 32 oriented orthogonal relative to underlying flow channel 30. Control recess 32 is separated from flow channel 30 by elastomer membrane 25. Membrane 25 is created from the same elastomeric material in which control recess 32 is formed. The floor of flow channel 30 may be formed from a rigid non-elastomeric substrate 14 such as glass, or may be formed from an underlying elastomer layer.
During operation, membrane 25 experiences an actuation force that causes it to deflect into and thereby obstruct a flow of material through the underlying flow channel. This is shown in FIG. 7H, which is a cross-sectional view of the valve structure of FIG. 7B in an actuated state. As described in detail in the '025 application, the actuation force displacing membrane 25 into the flow channel can take many forms, including but not limited to elevated pneumatic or hydraulic pressure within control recess 32 relative to flow channel 30.
Given the large number of potential applications for elastomeric microfluidic handling systems described in the '025 application, it is seen that alternative structures and methods for actuation are desirable.